Non-volatile resistance memory is a focus of memory research of electronic industry worldwide, and is regarded as a promising candidate for memory in future devices.
At present, resistive random-access memory (RRAM) devices require a comparatively large voltage to break the device down from a highly resistive initial state, in a so-called forming process, so as to enable subsequent resistance switching. Without the forming process, the device is essentially a bad insulator, and the device becomes an RRAM only after forming.
These electric forming processes, however, consume significant power and are usually very slow. In addition, electric forming creates conducting filaments, which are localized structures that undergo dielectric breakdown containing many defects of a wide variety, which are problematic. Further, electric forming results are highly dependent on the instrument and conditions used, as well as the device configurations and circuit characteristics. Without being bound to any particular theory, this is because the critical step in electrical forming is the nucleation of localized regions of dielectric breakdown under a huge transient current density, and such a dynamic process is difficult to reproducibly control in mass production.
Because of this challenging process, there is currently a barrier to uniform and reliable RRAM devices. Accordingly, there is a need for improved forming processes for electrical devices.